Projectile Control Surface Deployment via Hot Gas Actuation

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Solution Overview

Problem

Existing control surface deployment systems for projectiles with environmental seals are inadequate, as centripetal force alone is insufficient to overcome seal resistance, and spring-based mechanisms are heavy and inefficient for small diameter projectiles with high resistive seals.

Innovation Solution

A hot gas-based system comprising first and second gas generators, gas chambers, a piston wedge, and a barrel is used to break environmental seals and deploy control surfaces, with a seal-breaching element and a control surface actuation element working in conjunction to ensure complete deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spring-based control surfaces deployment mechanisms are used to overcome environmental seal resistance, then control surfaces can be deployed through seals, but the mechanism becomes relatively heavy and has low energy density

Engineering Contradiction:
Improvecontrol surface deployment capabilityVSAvoiddeployment mechanism weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the spring-based mechanical deployment mechanism with a hot gas-based actuation system. Hot gas generators create pressure differential to deploy control surfaces, eliminating the need for heavy mechanical springs while maintaining deployment capability through the environmental seal.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses hot gas (pneumatic system) to actuate control surface deployment. Hot gas generators produce high-temperature gas that creates pressure differential across the environmental seal, enabling lightweight actuation of control surfaces without mechanical springs.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Adaptability or versatility

If spring-based control surfaces deployment mechanisms are used, then deployment is possible for large diameter projectiles, but the mechanisms are ineffective for small diameter projectiles having more resistive environmental seals

Engineering Contradiction:
Improvedeployment effectiveness across different projectile sizesVSAvoiddeployment capability for small diameter projectiles
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The hot gas-based deployment system is designed to be universally applicable across different projectile diameters. The system can adapt to various seal resistances by adjusting hot gas generation parameters, making it effective for both large and small diameter projectiles where spring mechanisms fail.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention changes the actuation parameter from mechanical spring force to hot gas pressure. This parameter change enables the system to overcome highly resistive environmental seals on small diameter projectiles, where spring force is insufficient, while maintaining compatibility with larger diameter projectiles.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If centripetal force from rotational spinning is used to deploy control surfaces, then the system is simple, but the force is insufficient to overcome environmental seal resistance

Engineering Contradiction:
Improvedeployment system complexityVSAvoiddeployment force
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The patent merges two deployment mechanisms: centripetal force from projectile rotation and hot gas pressure from hot gas generators. The hot gas system provides additional force to overcome environmental seal resistance, while the centrifugal force completes the deployment, combining simplicity with sufficient force.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hot gas generators are activated before the projectile reaches sufficient rotational speed to generate adequate centripetal force. This preliminary action creates initial pressure differential to breach the environmental seal, after which centrifugal force completes the control surface deployment.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively deploys control surfaces through environmental seals of any thickness, regardless of projectile diameter or launch conditions, providing reliable and efficient control surface deployment.

Implementation Method 1

the first hot gas generator discharges a surge of hot gas into the first gas chamber. In response to the surge of hot gas being discharged into the first gas generator, the piston wedge displaces at least one of the control surfaces

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

the second hot gas generator discharges a surge of hot gas into the second gas chamber. The surge of hot gas displaces the piston and barrel for deploying the control surfaces completely

Methodology Applied
Scientific EffectHot gas expansion: Thermal Expansion

Data Source

PatentEP2748557B1Apparatus for deploying stowed control surfaces of a projectile
Publication Date: 2016.06.08 BAE SYSTEMS INC
  • EP2748557B1 patent drawingFigure 1A~1B
  • EP2748557B1 patent drawingFigure 2A
  • EP2748557B1 patent drawingFigure 2B

AI summary

An apparatus for deploying stowed control surfaces of a projectile is disclosed. The apparatus for deploying stowed control surfaces of a projectile includes a first and second hot gas generators, a first and second gas chambers, a piston wedge, a piston and a barrel. Initially, the first hot gas generator discharges a surge of hot gas into the first gas chamber. In response to the surge of hot gas being discharged into the first gas generator, the piston wedge displaces at least one of the control surfaces to break an environmental seal covering the projectile. After a predetermined amount of time has lapsed, the second hot gas generator discharges a surge of hot gas into the second gas chamber. The surge of hot gas displaces the piston and barrel for deploying the control surfaces completely.